Sewer gas smell in basement from sump pump

I have a sewer gas smell in my basement that is coming from the sump pump. I have been reading many posts on this site and others and believe I have diagnosed the problem. I want to confirm that my diagnosis is correct, see if there are any other possibilities that are possible with the given symptoms, and get a ballpark of how much it would cost for a professional to fix and if there is anything I can do myself to save money. I apologize in advance for my post being so long, but there always seem to be people who do not post all the needed information and are asked questions or are given answers that are not valid because of an incorrect assumption. Hopefully my situation and answers to my questions will also help other homeowner in similar situations.

A little background:
I am living in IL so the sump pump has only 1 inlet below the level of the concrete in the full basement which is about 7ft below ground. The pump has 1 output with a check valve that pumps above ground about 20’ away from the house. I believe this pump (and all sump pumps) should pump only ground water and not be directly connected to the city sewer. I have no septic system because my drains are connected to the city sewer system.

Symptoms:
There is a sewer smell coming from sump pump and sump pump running more often than expected. Some days the smell is barely noticeable in the basement and some days the smell is horrible and can even be smelled through the house from the vents. During the last hard rain ~1.5”/hr I timed the sump pump and it consistently ran for 20s of each 50s period (and was off for 30/50s.) This is almost a 50% duty cycle and if my power was to go out, I would have water in my basement in less than 1 minute. After measuring the sump as well as high and low water levels I calculated that the incoming water rate is 1000gal/hr (I attached the spreadsheet I made to calculate this). I do not smell anything outside the house or see any areas of the grass that are greener or grow faster than others. I have noticed the sump pump running excessively for about a year now but did not think much of it since we had recently moved in, but the sewer smell did not start until this spring and has gotten worse over the last few months.

Test:
This morning, I checked the sump; it has not rained in 3 days. There is a tiny amount of water coming in (1 drop every 3s). I then turned all the water faucets on in the house. After about 5 min the flow into the sump pump is significant and fills every 1.2 minutes (~8gal/min=480gal/hr).

Questions:
1)I’m guessing that the leak is from my sewer connection which exits the house through the foundation about 4’ below ground level & 4’ above the basement floor on the opposite side of the house from the sump. Is it possible that there are any other places where the water could be coming? (In another posting it was suggested that the leak may be under the foundation and very expensive to fix.)
2)I am planning on calling a professional plumber to at least find where the leak is with a pipe camera. But I do not want to get taken advantage of or tell him what I think it is in case it is something less serious. Is it generally better to say what I think it wrong even if it is not correct or let the plumber draw his own conclusions from his investigations?
3)Are there any special tools or expertise that I should ask the plumber about before hiring one?
4)Is there likely to be a large accumulation of “sewer materials” all along the foundation of my house between the sewer and the sump that would require digging up to avoid any further smell?
5)Should I call the city to fix this since it is a public sewer line that is likely broken? And if it is this public sewer line would the city fix it for free?
6)Can anyone give a ballpark of how much this will/could cost to fix? $500, $1000, $5000? Maybe you can give a range or max and min depending on how bad it is so I know what to expect. I can rent an excavator and do most of the digging myself if needed to save money.
7)I have seen another post that mentioned houses being built on farmland with leach fields without the drainage tiles removed. I do not think my problem is related to this. Does anyone disagree?
8)Any other information that I should know or questions for me?

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Sewer gas smell in basement from sump pump

The first thing I'd do is go to a hardware store or pool suppy company and get a bottle of water test strips. They can test for chlorination in the water, which will let you know if it is groundwater or sewer/waterline water. If it is chlorinated you have ruled out groundwater.

Quote:

Originally Posted by mirage212

Questions:
1)I’m guessing that the leak is from my sewer connection which exits the house through the foundation about 4’ below ground level & 4’ above the basement floor on the opposite side of the house from the sump. Is it possible that there are any other places where the water could be coming? (In another posting it was suggested that the leak may be under the foundation and very expensive to fix.)A sewer leak would easily get to the drain tile pipe that surrounds your house and connects to your sump pump.

2)I am planning on calling a professional plumber to at least find where the leak is with a pipe camera. But I do not want to get taken advantage of or tell him what I think it is in case it is something less serious. Is it generally better to say what I think it wrong even if it is not correct or let the plumber draw his own conclusions from his investigations?Hire a reputable plumber and put your trust in him. Companies with fleets of trucks and big advertising will overcharge and aren't always honest. Call the guy with a small ad in the phonebook. Personally, I'd want the guy with the plumbing license to be the guy that does my work, not a kid that works for him.

3)Are there any special tools or expertise that I should ask the plumber about before hiring one?No, if this is a sewer leak any good plumber can handle it.

4)Is there likely to be a large accumulation of “sewer materials” all along the foundation of my house between the sewer and the sump that would require digging up to avoid any further smell?It depends on the break, but I doubt there's anything that won't be solved after a couple good rainstorms wash the system out.

5)Should I call the city to fix this since it is a public sewer line that is likely broken? And if it is this public sewer line would the city fix it for free?You can try. Most of the time the homeowner is responsible for their sewer line between the house and the main line. The utility is responsible for the main line only.

6)Can anyone give a ballpark of how much this will/could cost to fix? $500, $1000, $5000? Maybe you can give a range or max and min depending on how bad it is so I know what to expect. I can rent an excavator and do most of the digging myself if needed to save money.No. This is a DIY site. Be warned that the plumber will probably charge more if you do your own digging...They make money off digging. Plus, they're not going to want you to cover their installation due to the risk of damage. I'd make you sign a waiver.

7)I have seen another post that mentioned houses being built on farmland with leach fields without the drainage tiles removed. I do not think my problem is related to this. Does anyone disagree?No. Septic fields are only poo-flavored for a short time. The earth absorbs it and it doesn't stay nasty too long.

8)Any other information that I should know or questions for me?

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Sewer gas smell in basement from sump pump

I've been calling around for quotations and one of the plumbers in the area said that he has seen a lot of this and it may be caused by the house settling and sheering the sewer lines since they are below ground. The house was built 15 years ago so I'm not too sure about this, but I think the crack is likely near the house since there is so much getting to the sump probably through the drain tiles.
I have PVC going into the foundation from the basement and about 3' from the house there is PVC sticking up out of the ground (access port) so I would assume that it continues to be PVC underground until at least that point. It would be ~$2k for them to fix so I'm going to start digging by hand 4' down to see if I can repair it myself. I will of course have to call the utilities to map out my yard first to make sure I don't hit gas lines or anything. The 2 plumbers I called did not seem to have any problems about me digging the hole myself to save money, but it sounds like it will not save as much money as I had hoped (1/2). But since the stock market is down almost 800 points today I should probably do whatever I can :-).
Before I start digging maybe I'll check in that access port to see if anything is flowing through there so I don't waste a day digging in the wrong spot.
I'll post again with whatever I find. Hopefully it's not too messy.

Last edited by mirage212; 09-29-2008 at 06:02 PM.
Reason: Forgot to add responce to last post about digging myself

Sewer gas smell in basement from sump pump

I performed one more test last night to confirm the location of the break. I am lucky enough to have access ports just inside the foundation and just outside (3' from the house). I first tried to use an electricl snake (for conduit) from the basement access port to see if I could feel the blockage or discontinuity. I really didn't fell anything so this made me unsure that the leak was near the foundation. But the test was not very good.
I then turned on the water from 1 faucet and was able to hear water flowing through the pipe inside the basement. I then went outside and looked down the access port and did not see any water flowing. I then tried 2 and then 3 faucets simultaneously and still did not see water flowing. I dropped a very small piece of debris down the hole and it did not move (also confirming no water flowing). To see any water flowing it took the larger volume of a toilet flushing. This confirms that the break is between the foundation and the access port 3' away. So I'll start digging; now confidant that I will find the problem in this small area.

Sewer gas smell in basement from sump pump

We've finished digging, it took 3 guys only about 2 hours to dig the 5' deep hole to see the PVC and then another 3 hours to get the last little bit around and under the pipe. The 4" PVC was cracked at the T junction which is about 3' from the foundation. the plan is to replace the T, add a small piece sticking out so we can add another piece with 2 couplings which have no gap. I had to Dremel the rib from the center of the coupling so that it would slide all the way on to the PVC and then slide over. The only problem is that the glue set before I could slide it back. I did it as quickly as I could (apply glue to pipe2, then pipe1, coupling, slide coupling on pipe1, slide coupling back to cover pipe2) but the coupling stuck on the pipe1 after about 5s so I could not slide it . So I cut a new short pipe and got a new coupling and it is now dry-fit as seen in the picture, but I am afraid to try to cement it again since it is a pain in the a$$ to dremel the center away enough. It leaks a bit now with the temporary dry fitting, but it is not nearly as bad as it was; I want to make sure it's fixed right so I don't have to do this again.

Should I try to find a slow setting PVC cement? I can find them online but not in home inmprovment stores.

Is there a better way to do this other than what I'm attempting?

Normally I'd apply PVC cement to both surfaces and then join as I tried to do. Will the joint be adequate if I slide the coupling on dry (with the center rib removed), then add cement on only the outside pipe surfaces and push the coupling over, or will the cement just be pushed away? If this will work, it would eliminate the need for a slower drying PVC cement.

Lowes had a rubber coupling, but I'm not sure if this is OK to bury, I would think it would not last very long.

Sewer gas smell in basement from sump pump

I wouldn't bury a Fernco (rubber) fitting in this application.

No, you can't get away with slathering a dry-fit joint with cement on the outside of the hub. Don't spend all this effort to half-ass the repair by doing that! You need to be using PVC primer/cleaner and then glue.

I haven't ever seen or used slow-setting PVC cement, so I can't weigh in on that.

You should be able to get slip-type couplings that won't require you to dremel the inside part out. Might have to hit a plumbing supply store for that though.

Sewer gas smell in basement from sump pump

I did not mean to just add cement around the coupling. The plan was to put the pipe in place, slide the couplings back away from the joint, then add glue to the pipe where the coupling will go, then slide the couplings in place over the pipes with cement. The only problem is that there will be no cement applied directly to the inside of the couplings and since the joint is tight, most of the cement may be pushed away when I slide the couplings in place over the pre-glued pipes. Maybe the couplings that are sold without a center rib fit slightly looser so this is not a problem. I'll check it out tonight along with the slow setting cement.

I would think the one with the largest maximum pipe size would be best because a larger pipe would generally take longer to move into place and would have larger gaps to fill. The IPS2719 can be used on up to 30" diameter PVC. I'll try to find that in a plumbing store around my house.

Sewer gas smell in basement from sump pump

I purchased a slow set PVC cement and primer at a local plumbing supply company. I used Hercules 60215 which is slow set and works on pipes up to 15" in diameter. It worked much better than the standard PVC cement and gave me a good 15 seconds to fit both pipes instead of 4 seconds which the standard PVC cement gave me. It is also very thick so it will fill any gaps much better. I applied primer (generously) to all 4 pipe connections and both sides of the 2 couplers, and then applied the cement (also generously) to everything. I then slid on on the long fixed pipe and the other on the short pipe to fill the gap. I then quickly slid the coupler from the short pipe to the second fixed pipe and then the coupler from the first fixed pipe to the short pipe. I was not able to find any couplings without center ribs at any stores and no one had heard of them; so to do this smoothly I had to dremel more from the inside of the coupler so I did not need a hammer to slide the couplers around on the pipe, although they were very tight to move by hand. After this was dry I placed paper towels under each joint, turned all the water on in the house for 10min, and checked the paper towels for any moisture. There was none... so no leaks. I then looked in the sump pump and not a drop was falling into it. So... PROBLEM SOLVED :-) (also the sewer smell had gotten much better since the dry fit). Now I'll wait for the inspector to check the pipes, fill the hole with the 18" of gravel that was removed then the clay, and lastly the topsoil and the small bush that I had to remove.

Last edited by mirage212; 10-21-2008 at 08:21 PM.
Reason: Mistake in first post

Sewer gas smell in basement from sump pump

mirage 212, thanks for posting your solution. I encountered the same problem trying to put a coupling on an existing underground pipe and now if I ever have to do that again I'll know about the slow setting cement. Bet you saved a few bucks.

Sewer gas smell in basement from sump pump

Quote:

Originally Posted by thekctermite

I don't think it is legal to bury a union. Most plumbing unions require that they're readily accessible.

Is that a union rule, a code rule, or a city rule<g>? Pun intended.
I can see your point. It was just a thought. Actually, I would not have done that kind of work myself. I have to hand it to Mirage212 for tackling the job himself.